Groundwater has been and continues to be a significant problem for buildings, especially for buildings with basements and crawl spaces. The floor of a basement typically comprises a several-inch-thick slab of concrete, poured upon a layer of crushed stone. If the surrounding water table stays below the crushed stone layer there may not be water problems in the basement. However, when the groundwater rises above the crushed stone it begins to adversely affect the building. The basement floor and basement walls become damp and/or leak. This is very undesirable. The past and present solutions to this problem are to simply collect and remove enough groundwater to keep hydraulic forces at an acceptable level. Typically, a sump located at the lowest point in a building's foundation drainage system, and a pump employed to evacuate the sump, discharging the water far enough from the building to be of no further concern.
Usually the sump is excavated at the time of the building's construction. The sump is basically a reservoir into which a cylindrical liner is placed; the liner is closed at the bottom and open at the top, and is typically constructed of polyethylene or other plastic resins. The liner defines ports along its cylindrical sidewall through which groundwater flows and collects in the reservoir. The sump liner is installed such that its open end will be flush with the adjacent finished floor. Sumps excavated subsequent to construction of the floor require removal of a sufficient amount of the floor along and underlying material to receive the liner. Then, concrete is poured around the sump liner to seal it in.
Most sump liners have inlet ports and/or are perforated for receiving drainage water from about the building's foundation footing tile drainage system through it and from groundwater beneath the basement floor. Drainage water then collects in the liner. When sufficient water has thus accumulated, a pump installed in the sump, commonly called a sump pump, is actuated and evacuates most of the water in the sump into a sewer or to a location outside the building.
Sump pumps are electromechanical in nature and consist of an impeller driven by an electric motor, all of which is contained within a housing. A float switch that closes when the water level rises to a point in the sump that would justify the energy expenditure to remove it controls operation of the pump. These switches are either separate from or integrated with the pump. The switch opens and pumping stops before the water in the sump reaches the level at which the pump can no longer function due to ingestion of air at the pump's intake. Therefore, in normal cycle duty of the sump-pumping system the pump is always at least partially immersed in water. The discharge water from the pump enters a drainage pipe or hose that leads to a location outside the building such as a field, lawn, or storm sewer.
However, as many homeowners have learned to their chagrin, sump pumps are not infallible. When a sump pump fails the first event that occurs is the sump liner overfills and floods the basement floor. The water level in the basement continues to rise until equilibrium is established, meaning the water level in the basement rises until it equals the level of the surrounding water table. This results in numerous problems for the building owner including: severe flooding inside the building, damaged or destroyed property, disagreeable odors that permeate the building, structural damage to the building, and temporary loss of use of the basement. Then, even after the basement is pumped dry, longer-lasting problems may take root including: shifting of the building's foundation, malodorous problems throughout the building, and the unhealthful growth of molds, mildews, and bacteria in the basement. All of these longer-lasting problems result in increased expense to make the building and basement habitable again and may result in decreased property value.
That every sump pump manufactured to date will fail is a statistical certainty, and therefore no pump can be depended on to function as originally designed for and unlimited amount of time. The reasons for eventual pump failure are many fold, and include at least the following: wear from friction; corrosion and electrolytic action caused by being immersed in contaminated water for its entire life, wreaking havoc on metallic surfaces; failure of seals and O-rings which results in the admission of water to components that must remain dry; accumulations of silt and other debris in the sump that can clog the pump intake, resulting in its inability to pump at the required rate, if it can pump at all; and obstructions in the discharge pipe that will disable a sump pump. Additionally, manufacturer defect in design or assembly must be recognized as a cause of pump failure.
Attempts to solve the problems associated with sump pump failure include use of a backup pump. However, the present use of backup sump pumps is not without problems. A sump liner provides for a relatively small diameter hole/opening, and to place a second pump internal to the sump is a difficult task. Additionally, complicated structural arrangements are called for when a backup sump pump is provided for in a sump liner, which necessitates use of a plurality of parts, some of which are small and intricate. There is also the high risk that separate floats for the separate pumps will become entangled, disabling both pumps. These parts must then be regularly maintained and examined since they can quickly deteriorate and become nonfunctional. Another way in which a backup pump has been used is to position a backup utility pump on the basement floor adjacent to the sump, instead of placing it within the sump liner. This also is not a satisfactory solution because not only does this arrangement present major problems in providing a reliable way to operate the pump when needed, but the backup pump is exposed to all the activities being carried out in the basement, such as people working in the basement, curious children exploring/playing in the basement, pets, and so forth. There is a high probability that one or more of these factors will conspire to render the backup pump inoperative without the knowledge of the building owner. If this happens, the backup sump pump will be of no use if the primary sump pump fails. In addition, such an exposed backup pump is constantly visible and is therefore aesthetically unappealing.
Thus, there is a need for a better sump liner, methodology, and system for preventing flooded basements and the damage associated therewith that is reliable and easy to use, yet overcomes the numerous problems and shortcomings associated with the above-described sump pump arrangements.